Potential benefits of cool roofs on commercial buildings: conserving energy, saving money, and reducing emission of greenhouse gases and air pollutants

作者：Ronnen Levinson, Hashem Akbari · 发表于：Energy Efficiency · 年份：2009 · DOI：10.1007/s12053-008-9038-2 · 被引用次数：266 · 研究领域：Urban Heat Island Mitigation、Building Energy and Comfort Optimization、Thermal Radiation and Cooling Technologies

Cool roofs—roofs that stay cool in the sun by minimizing solar absorption and maximizing thermal emission—lessen the flow of heat from the roof into the building, reducing the need for space cooling energy in conditioned buildings. Cool roofs may also increase the need for heating energy in cold climates. For a commercial building, the decrease in annual cooling load is typically much greater than the increase in annual heating load. This study combines building energy simulations, local energy prices, local electricity emission factors, and local estimates of building density to characterize local, state average, and national average cooling energy savings, heating energy penalties, energy cost savings, and emission reductions per unit conditioned roof area. The annual heating and cooling energy uses of four commercial building prototypes—new office (1980+), old office (pre-1980), new retail (1980+), and old retail (pre-1980)—were simulated in 236 US cities. Substituting a weathered cool white roof (solar reflectance 0.55) for a weathered conventional gray roof (solar reflectance 0.20) yielded annually a cooling energy saving per unit conditioned roof area ranging from 3.30 kWh/m2 in Alaska to 7.69 kWh/m2 in Arizona (5.02 kWh/m2 nationwide); a heating energy penalty ranging from 0.003 therm/m2 in Hawaii to 0.14 therm/m2 in Wyoming (0.065 therm/m2 nationwide); and an energy cost saving ranging from 0.126/m2 in West Virginia to 1.14/m2 in Arizona ( 0.356/m2 nationwide). It als...